(a) Field of the Invention
The present invention relates to a pick-up apparatus for two or more semiconductor chips having different sizes, and more particularly to apparatus capable of selectively picking-up conductor chips without replacing a pick-up holder for the semiconductor chips.
(b) Description of the Related Art
In the manufacture of semiconductor chips, semiconductor chips are separated by using a full-cut dicing technique from a semiconductor wafer after fabrication of thin film layers thereon. After a specified test, only the qualified chips are picked up from a production line by a push-up pin.
The semiconductor chips to be picked up have different sizes depending on the type of the semiconductor chips.
In a conventional pick-up technique for semiconductor chips, the main purpose is to pick up the semiconductor chips without causing damage thereto as described in JP-A6(1994)-18636, for example. In the described technique, the chips are picked up and peeled off from an adhesive tape by a push-up pin in a push-up holder. Since the pin pitch of the push-up pin is fixed, the size of the push-up pin must be changed in accordance with the size of the chips, and conventionally a pin holder is replaced with another pin holder having a different pin pitch depending on the chip size. The change of the pushup pin is generally achieved by replacement of the push-up holder and the pin holder as a whole, thus requiring a long period of time. For smoothly conducting the replacement, a plurality of pin holders the number of which is dependent on the chip sizes must be stored and the control of the stocked tools is also required.
Referring to FIGS. 1A and 1B, in a conventional apparatus for picking up semiconductor chips 31a and 31b having different sizes, each of chips 31a and 31b is picked up by each of ascending push-up pins 32a and 32b having a somewhat smaller pin pitch than an outer size of the chips 31a and 31b mounted on each of pin holders 33a and 33b. FIG. 1A shows a larger chip (FIG. 1A) having a pin pitch (La) and FIG. 1B shows a smaller chip having a pin pitch (La) In order to respond to the size change of the chips, the pin holder mounted on the pick-up apparatus is replaced with another having a different size fitting the chip size.
The replacement of the pin holder is quite burdensome to largely lower the fabrication efficiency. Although such a burdensome and low-efficient procedure conducted in a relatively simple operation such as the pick-up of the semiconductor chips is a serious problem, a technique or an apparatus for simply picking up semiconductor chips having different sizes has scarcely attracted attention in the field.
In view of the foregoing, an object of the present invention is to provide an apparatus for simply and effectively picking up semiconductor chips having different sizes without employing a burdensome and inefficient procedure.
The present invention provides an apparatus for picking up semiconductor chips including a composite cam formed by a plurality of cylindrical cams having different diameters and upward projections out of phase with one another, and a plurality of cylindrical pin holders separately movable in a vertical direction and having a plurality of push-up pins at an upper portion and a plurality of downward projections out of phase with one another; at least part of the pin holder positioned above the composite cam being in contact with the composite cam and the number of the pin holders being the same as that of the cylindrical cams. The plurality of the cylindrical cams forming the composite cam of the present invention may be integrated or separately rotated.
In accordance with the present invention, a specified one of the pin holders which properly picks up a corresponding semiconductor chip can be selected, and even when another chip having a different size is required to be picked up, another pin holder well-fitted for the chip is selected by rotating the composite cam without replacing the pin holder with another one.
In this manner, the replacement between the pin holders each suited for picking up semiconductor chips having different sizes can be eliminated. Accordingly, a period of time and labor required for the replacement can be saved, and the management of elements to be replaced is no longer necessary, and a simple operation of the lever enables the pick-up of a desired semiconductor chip.
The above and other objects, features and advantages of the present invention will be more apparent from the following description.